1. Field of the Invention
This invention relates to a process for the preparation of an "A-alpha" single stereoisomer of an S-alpha-cyano-3-phenoxybenzyl S-alpha-isopropylphenylacetate in substantially pure form or of a mixture enriched in said "A-alpha".
2. Description of the Prior Art
S-alpha-cyano-3-phenoxybenzyl S-alpha-isopropylphenylacetates are of interest because this "A-alpha" isomer has high pesticidal activity as compared to the racemic mixture, any of the diastereoisomer pairs or other single stereoisomer forms of such alpha-cyano-3-phenoxybenzyl alpha-isopropylphenylacetates. While various methods have been proposed to prepare the "A-alpha" isomer, they have had a number of limitations for practical use, e.g. because they have required cumbersome methods of classical resolution of the acid.